Heat sink for electronic parts and manufacture thereof

ABSTRACT

Heat dissipation fins  12  provided on a metal flat plate  10  with a predetermined distance and a metal base plate provided with a plurality of bottom-expanded recesses  15  on the flat surface  14  with a predetermined distance are prepared and pressing portions corresponding to the bottom-expanded recesses on the flat plate between fins to press down protrusions provided on the back side of the flat plate into the bottom-expanded recesses to fix the heat dissipation fins and the base plate securely. Number of components of the heat sink is reduced and construction has become simple. The manufacturing cost is reduced.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a heat sink for electronic partsand more particularly relates to a heat sink for electronic parts madeof Transistor, IC, LSI, Diode or Thyristor to cause heat duringpractical operation, the heat being conducted and dissipated from theheat sink fins.

[0003] 2. Prior Art

[0004] Conventional heat sink made of aluminum has been disclosed in theJapanese Patent Publication No. 3-40506. Reference is made with FIG. 1to explain such conventional heat sink. A substrate 1 made of aluminumand heat dissipation fins 2 formed by bending aluminum band sheets intothe rectangular corrugated plate are soldered to prepare a heat sink. Inthe process of manufacturing heat sink, two vertically protruded edgeframes 3, 3 provided in parallel with each other at each edge of thesubstrate 1 respectively are formed on the substrate 1 with apredetermined distance. The heat dissipation fins are placed betweensaid oppositely faced protruded edge frames 3, 3. As shown in FIG. 1,the heat dissipation fins extend to a full width between the protrudededge frames 3, 3 provided on the substrate 1 in parallel with eachother, and a portion of the protruded edge frame 3 where the heatdissipation fins 2 and said protruded edge frame 3 come into contactwith each other is pressed by means of a mold to stretch out saidportion toward inside the substrate 1. Reference numeral 3 a indicatesthe portion stretched out inside the substrate 1 in FIG. 1. The portions3 a, 3 a secure the heat dissipation fins 2 to the substrate 1. Next,the substrate 1 and the heat dissipation fins 2 are soldered together.

[0005] It has been pointed out in the conventional method that the heatdissipation fins 2 and the substrate 1 are to be soldered because if theheat dissipation fins 2 are secured to the substrate 1 only by means ofthe aforementioned portions 3 a, 3 a, the heat dissipation fins 2 willnot perfectly contact the substrate 1 and the heat generated in thesubstrate 1 is not perfectly conducted to the heat dissipation fins 2.

[0006] It is, therefore, required in the conventional manufacturingmethod of heat sink to solder the heat dissipation fins 2 to thesubstrate 1. However, in order to proceed the soldering process somesoldering installments are inevitably required. This is a problem inconventional method.

[0007] Further, as bending the aluminum band sheet into a rectangularcorrugated sheet makes the heat dissipation fins, plate thickness of theheat dissipation fins is limited to be thinner taking into considerationof easy handling. Accordingly, if the heat dissipation fins made ofthinner plate should collide other materials such as electronic parts orhousings or the like, the fins are easily distorted.

[0008] The present invention has been made with the foregoing backgroundin mind. The object of the present invention is to offer an easyprocessing method and yet most durable heat sinks for electronic partsand manufacture thereof.

SUMMARY OF THE INVENTION

[0009] In order to achieve the aforementioned object the presentinvention offers a heat sink disclosed in claim 1 and illustrated inFIG. 2A and 2B. The heat sink according to the present inventioncomprises a plurality of heat dissipation fins 12 and a base plate 16.The heat sink includes heat dissipation fins 12 provided with aplurality of fins 11 placed on the upper surface of a metal plate 10with a predetermined distance, and the metal base plate 16 provided witha plurality of bottom-expanded recesses 15 on the upper surface of aflat plate 14 with a predetermined distance. Portions corresponding tothe bottom-expanded recesses 15 of the flat plate 14 between the fins 11are pressed by means of a mold 18 so that protrusions 13 (refer to FIG.3B2) provided on the back side of the metal plate 10 are pressed intothe bottom-expanded recesses 15 to fix the heat dissipation fins 12 andthe base plate 16 together.

[0010] The invention disclosed in claim 2 comprises, as brieflyillustrated the overall construction in FIG. 4A, 4B, 4C, heatdissipation fins 12 provided with a plurality of fins 11 placed on theupper surface of the flat plate 10 with a predetermined distance and ametal base plate 16 provided with a plurality of bottom-expandedrecesses 15 on the upper surface of a flat plate 14 with a predetermineddistance and protrusions 17, 17 to hold the side edges of said heatdissipation fins 12 to secure said heat dissipation fins 12 on the uppersurface of a flat plate 14. Portions of the flat plate 10 correspondingto the bottom-expanded recesses 15 between said two fins 11 are pressedby the mold 18 to press down protrusions 13 (refer to FIG. 3B2) providedon the back side of said flat plate 10 into said bottom-expandedrecesses 15 and the protrusions 17, 17 formed on the base plate 16 arepressed and distorted toward the side of the heat dissipation fins 12 tofix said heat dissipation fins 12 to the base plate 16.

[0011] The invention disclosed in claim 3 comprises heat dissipationfins 12 provided with a plurality of fins 11 placed on the upper surfaceof the metal plate 10 with a predetermined distance and a metal baseplate 16 provided with a plurality of bottom-expanded recesses 15 on theupper surface 14 with a predetermined distance, and the portions of theflat plate 10 corresponding to the bottom-expanded recesses 15 betweensaid two fins 11 are pressed by the mold 18 to press down protrusions 13(refer to FIG. 3B2) provided on the back side of said flat plate 10 intosaid bottom-expanded recesses 15 to fix the dissipation fins 12 and thebase plate 16 together. This is the manufacturing process of the heatsink disclosed in claim 1.

[0012] The invention disclosed in claim 4 comprises the heat dissipationfins 12 provided with a plurality of fins 11 placed on the upper surfaceof the metal plate 10 with a predetermined distance and a metal baseplate 16 provided with a plurality of bottom-expanded recesses 15provided on the upper surface 14 with a predetermined distance andprotrusions 17, 17 to hold the side edges of the heat dissipation fins12 to secure said heat dissipation fins 12 on the upper surface of aflat plate 14. Portions of the flat plate 10 corresponding to thebottom- expanded recesses 15 between said two fins 11 are pressed by themold 18 to press down protrusions 13 provided on the back side of saidflat plate 10 into said bottom-expanded recesses 15 and the protrusions17, 17 formed on the base plate 16 are pressed and distorted toward theside of the heat dissipated fins 12 to fix said heat dissipated fins 12to the base plate 16. This is the manufacturing process of the heat sinkdisclosed in claim 2.

BRIEF EXPLANATION OF THE DRAWINGS

[0013]FIG. 1 is a perspective view of the conventional aluminum heatsink.

[0014]FIG. 2 indicates a heat sink for electronic parts disclosed inclaim 1 according to the present invention.

[0015]FIG. 3 illustrates a manufacturing process for the heat sink forthe electronic parts disclosed in claim 3 according to the presentinvention.

[0016]FIG. 4 indicates a heat sink for the electronic parts disclosed inclaim 2 according to the present invention.

[0017]FIG. 5 illustrates a manufacturing process for the heat sink forthe electronic parts disclosed in claim 4 according to the presentinvention.

[0018]FIG. 6 indicates another example of the preferred embodiments forthe heat sink for the electronic parts disclosed in claim 2 according tothe present invention.

[0019]FIG. 7 indicates a cross-section partly cut the heat sink for theelectronic parts disclosed in claim 2 according to the presentinvention.

DETAILED EXPLANATION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

[0020] Now an example of the preferred embodiments of the heat sinkdisclosed in claim 1 according to the present invention is explainedwith reference to the accompanying drawing FIG. 2A, 2B and 2C.

[0021]FIG. 2A indicates a perspective view of the heat sink according tothe present invention. FIG. 2B indicates a perspective view of the baseplate. FIG. 2C indicates a perspective view of the heat sink for theelectronic parts comprising the heat dissipation fins are pressed by themold to fix the heat dissipation fins to the base plate. The heat sinkaccording to the present invention is prepared by extruding a metal ofgood heat conduction such as aluminum or the like. The heat sinkcomprises heat dissipation fins 12 provided with a plurality of fins 11formed on the flat metal plate 10 with a predetermined distance and abase plate 16 provided with a plurality of bottom-expanded recesses 15formed on the flat plate 14 with a predetermined distance. As shown inFIG. 2C, the portions corresponding to the bottom expanded recesses 15on the flat surface 14 between the fins 11 are pressed down by means ofthe mold 18 to press down protrusions 13 (refer to FIG. 3B2) provided onthe back side of said flat metal plate 10 into said bottom-expandedrecesses 15 to fix said plurality of heat dissipation fins 12 and thebase plate together. The bottom-expanded recesses 15 are made likedovetail grooves in the embodiments of the present invention. It is ofcourse possible to form a recessed hole of dovetail groove. The recessedhole of dovetail groove configuration is not made by means of pressextrusion but other extrusion method is applied. Reference numeral 18 aindicates protrusions to press and distort the flat metal plate 10provided on the mold

[0022] As aforementioned, the heat sink according to the presentinvention is made by pressing down the protrusions 18 a provided in themold 18 to press the corresponding portions to the bottom-expandedrecesses 15 of the flat metal plate 10 between the fins 11 to press downsaid protrusions 13 into the bottom-expanded recesses 15 to fix the heatdissipation fins 12 to the base plate 16. The soldering installation isnot required. Thus, manufacturing cost is reduced.

[0023] The heat sink for electronic parts disclosed in claim 2 of thepresent invention is explained with reference to the drawings FIG. 4A,4B and 4C. FIG. 4A is a perspective view of the heat sink. FIG. 4B is aperspective view of the base plate. FIG. 4C is a perspective view of theheat sink for electronic parts prepared by pressing the heat sink to thebase plate by means of the mold. The heat sink for electronic partscomprises a heat sink provided with a plurality of heat dissipation fins12 formed on the surface of the flat metal plate 10 with a predetermineddistance and the base plate 16 provided with the protrusions 17, 17 tohold the both ends of said heat dissipation fins 12 on the surface ofthe flat plate 14 with a predetermined distance to hold together withthe plurality of bottom-expanded recesses 15. The corresponding portionto the bottom-expanded recesses 15 on the flat plate 10 between the fins11 is pressed down by means of the mold 18 to press the protrusions 13provided on the back side of the flat metal plate 10 into said recesses15 (refer to FIG. 5B2). The holding protrusions 17, 17 formed on theedge plate 16 are pressed and distorted toward the side of the heatdissipation fins 12 to fix said heat dissipation fins 12 and the baseplate 16 tightly to prepare heat sink for electronic parts according tothe present invention.

[0024] Reference numeral 18 b indicates a press protrusion to press anddistort the holding protrusions 17. It is possible to construct the heatdissipation fins 12 and the base plate 16 simply and perfectly fixedtogether without soldering. Both edges of the heat dissipation fins 12are held firmly by being held with the protrusions 17, 17. The heatdissipation fins 12 and the base plate 16 are fixed tightly. A durableconstruction is obtained.

[0025] In this embodiment, two protrusions 17, 17 are formed to hold theboth ends of the heat dissipation fins 12 facing with each other. Itgoes without saying that holding another both ends of the heatdissipation fins 12 by additional protrusions 17, 17 provided crossingat right angle to the edge side protrusions 17, 17 can offer moredurable structure of heat dissipation fins (not shown in figure).

[0026] The manufacturing process of the heat dissipation fins disclosedin claim 3 according to the present invention is explained withreference to the accompany drawing FIG. 3A1, 3A2, 3B1 and 3B2. Firstly,the heat sink is prepared by extruding a metal of good heat transmissionsuch as aluminum or the like. The heat sink comprises heat dissipationfins 12 provided with a plurality of fins 11 formed on the plate 10 witha predetermined distance and a base plate 16 provided with a pluralityof bottom-expanded recesses 15 formed on the flat plate 14 with apredetermined distance. As shown in front view of FIG. 3A1 and rightside view of FIG. 3A2, a plurality of heat dissipation fins 12 areprovided on the base plate 16. Next, as shown in front view of FIG. 3B1and right side view of FIG. 3B2, the corresponding portion of the flatplate 10 to a plurality of bottom-expanded recesses 15 between the fins11 are pressed down by means of the mold 18 to press insert theprotrusions 13 provided on the back side of the flat plate 10 into thebottom-expanded recesses 16 to fix said heat dissipation fins 12 andsaid base plate 15 securely.

[0027] In accordance with this manufacturing process of the heat sinkfor electronic parts, said heat dissipation fins 12 and the base plate16 are perfectly fixed without soldering. The manufacturing process issimple but securely fixed construction is obtained. The manufacturingcost is reduced. The manufacturing process of the heat sink forelectronic parts disclosed in claim 4 is explained with reference toFIG. 5A1 and 5A2. At first, the heat dissipation fins 12 provided with aplurality of fins 11 on the flat plate 10 with a predetermined distanceand the base plate 16 provided with a plurality of the bottom expandedrecesses 15 formed on the plate surface 14 with a predetermined distanceand further provided with the holding protrusions 17, 17 to hold theedges of said heat dissipation fins 12 are prepared by extruding a metalof good heat conduction such as aluminum. Next, as shown in front viewof FIG. 5A1 and right side view of FIG. 5A2, the corresponding portionson the flat plate 10 between the fins 11 to the bottom-expanded recesses15 are pressed down by means of the mold 18 to press insert saidprotrusions provided on the back side of said flat plate 10 into thebottom-expanded recesses 15 and at the same time the holding protrusions17, 17 provided on the base plate 16 to press and distort saidprotrusions 17, 17 toward the side of the heat dissipation fins 12.

[0028] The heat dissipation fins 12 and the base plate 16 are fixed asaforementioned. The heat sink for electronic parts according to thepresent invention is prepared without soldering. The heat dissipationfins 12 and the base plate 16 are fixed together. A durable constructionis obtained. If holding protrusions 17, 17 are pressed to distort towardthe side of the heat dissipation fins 12, the fins 11 are stronglysupported and the heat dissipation fins 12 are tightly held to the baseplate 16.

[0029]FIG. 6A, 6B and 6C indicate another example of the preferredembodiments of the present invention. FIG. 6A is a perspective view ofthe heat dissipation fins 12. FIG. 6B is a perspective view of the baseplate 16. FIG. 6C is a perspective view of the heat sink for electronicparts prepared by pressing the heat dissipation fins 12 toward the baseplate 16. FIG. 7 is a partly vertical cross-section of the heat sinkshown in FIG. 6. In this embodiment, the heat sink is pressed at theportions corresponding to said bottom expanded recesses 15 of the flatplate 10 between fins 11, 11 by means of the mold 18 to press down theprotrusions provided on the back side of the flat plate 10 into thebottom expanded recesses 15 and the holding protrusions 17, 17 providedon the base plate 16 are slightly bent toward the side of the heatdissipation fins 12. The portion 17 a is pressed down to cover the edgesof the flat plate 10 of the heat dissipation fins 12. As shown in FIG.6C, the press mold 18 is devised to press down the portion 17 a betweenthe fins 11 of the holding protrusion 17 to cover the flat plate 10 ofthe heat dissipation fins 12 (e.g. dividing the press protrusion 18 b ofthe mold 18).

Effect of the Invention

[0030] As aforementioned, claim 1 (heat sink) and claim 3 (manufacturingmethod of the heat sink) present a heat sink by pressing the portioncorresponding to the bottom-expanded recesses of the flat plate betweenthe fins by means of the mold to press the protrusions provided on theback side of the flat plate toward the base plate to press down theprotrusions into the bottom-expanded recesses. The perfectly fixedconstruction of the heat dissipation fins and the base plate isobtained. The manufacturing process is done without solderinginstallation. The manufacturing cost is greatly reduced.

[0031] As aforementioned, claim 2 (heat sink) and claim 4 (manufacturingmethod of the heat sink) present a heat sink by fixing the heatdissipation fins and the base plate without soldering. The heatdissipation fins are fixed at its ends to the base plate with theholding protrusions. Construction of the heat dissipation fins with thebase plate is firm.

What is claimed is:
 1. A heat sink for electronic parts comprising: aplurality of heat dissipation fins provided on a metal flat plate with apredetermined distance, a metal base plate provided with a plurality ofbottom expanded recesses on the flat surface with a predetermineddistance, pressing a portion corresponding to the bottom-expandedrecesses provided on the flat surface between the fins to press downprotrusions provided on the back side of the metal flat plate to pressinto the bottom-expanded recesses to fix the heat dissipation fins andthe base plate securely.
 2. A heat sink for electronic parts comprising:a plurality of heat dissipation fins provided on a metal flat plate witha predetermined distance, a metal base plate provided with a pluralityof bottom-expanded recesses on the flat surface with a predetermineddistance, and the base plate provided with a holding protrusions to holdboth ends of the heat dissipation fins. pressing the portioncorresponding to the bottom-expanded recesses of the metal flat platebetween fins and to press the protrusions provided on the back side ofsaid flat plate to press into said bottom-expanded recesses and to pressthe holding protrusions provided on the edges of the base plate towardthe side of the heat dissipation fins to fix said heat dissipation finsand the base plate securely.
 3. A manufacturing process of a heat sinkfor electronic parts comprising: a plurality of heat dissipation finsprovided on a metal flat plate with a predetermined distance and a metalbase plate provided with a plurality of bottom-expanded recesses on theflat surface with a predetermined distance are prepared, and pressing aportion corresponding to the bottom-expanded recesses of the flat platebetween the fins to press down protrusions provided on the back side ofthe flat surface plate to press into the bottom-expanded recesses to fixthe heat dissipation fins and the base plate securely.
 4. Amanufacturing process of a heat sink for electronic parts comprising: aplurality of heat dissipation fins provided on a metal flat plate with apredetermined distance, a metal base plate provided with a plurality ofbottom-expanded recesses provided on the metal flat surface with apredetermined distance, and the base plate provided with a holdingprotrusions to hold at both ends of the plate, pressing the portionscorresponding to the bottom-expanded recesses of the flat plate betweenfins and to press down the protrusions provided on the back side of saidflat plate into said bottom-expanded recesses and to press the holdingprotrusions provided on the base plate toward the side of the fins tofix the heat dissipation fins and the base plate securely.